The restorative action of coenzyme Q10 in 2,4-dinitrophenol-depressed electrical and contractile activities of guinea-pig heart.

With electrophysiological methods, mechanisms of the restorative action of coenzyme Q10 (CoQ10) in 2,4-dinitrophenol-depressed electrical and mechanical activities of isolated guinea-pig hearts were studied. Isoproterenol (3 X 10(-8) M)-induced action potential and contraction of the heart in 27 mM KCl Tyrode solution were abolished by 6 X 10(-6) M 2,4-dinitrophenol, while the additional application of CoQ10 (50 micrograms/ml) restored both these activities of the heart. This restorative action of CoQ10 was dose related (2 to 50 micrograms/ml) and was inhibited by 10 micrograms/ml 15-hydroperoxyarachidonic acid (15-HPAA) or pretreatment of the animals with indomethacin (5 mg/kg i.v.). When exogenously applied, 200 ng/ml prostacyclin also restored the 2,4-dinitrophenol-depressed electrical and contractile activities of the heart, but this restorative action of prostacyclin was affected neither by 15-HPAA nor by indomethacin pretreatment. These results suggest the possible participation of prostacyclin in the restorative action of CoQ10 in 2,4-dinitrophenol-depressed electrical and mechanical activities of the heart.